Walk and bridge plank



A. ZAGBLMBYBR. WALK AND BRIDGE PLANK.

Patented Sept. 13., 1892.

. of the suns rays and wind, so that each plank Unirse STATES PATENTrerun.

ALEXANDER ZAGELMEYER, OE VEST BAY CITY, MICHIGAN.

WALK -AND BRIDGE PLAN K.

SPECIFICATION forming part of4 Letters Batent No. 482,536, datedSeptember 13, 1892..

Application iilerl November 16, 1891. Serial No. 412,025. (No model.)

To if/ZZ whom t may concern:

Be it known that I, ALEXANDER ZAGEL- MEYER, a citizen of the UnitedStates, residing at West Bay City, in the county of and State ofMichigan,have invented certain new and useful Improvements` in W'alk andBridge Planks, of which the following is a specification, referencebeing had therein to the accompanying drawings.

The invention relates to improvements in plank for sidewalks, bridges,dac., and pertains particularly to the form and contour of the uppersurface of the plank. It is well known that the planks used for bridges,sidewalks, dac., are usually laid upon and secured to stringers, and arenecessarily supported in close proximity to the ground, so that theunder side of the planks are continually exposed to dampness andconfined atmosphere beneath, while the upper opposite sides thereof areexposed to acontinual dryinginfluence in a short time after layingbecomes warped or curved transversely, so that its lateral edges areturned slightly upward and a shallow trough in each plank is formed,which in every shower provides a receptacle for holding water, and this,while being of great annoyance and inconvenience to pedestrians, alsocauses a continual soaking and drying action to obtain in the wood fiberand cells, with the result of quickly destroying' the plank by rot; andthe object is to so construct a plank for the purpose mentioned as toallow the water caught upon the surface to quickly run off, whereby onlythe outer and exposed wood ber is liable to become saturated and wherebythe plank is quickly and easily dried and hardened and the period ofwear of the plank is prolonged and a walk clear of waterpools anddampness is provided.

My invention consists in a plank for sidewalks, bridges, dtc., havingits upper surface ofa convex form transversely; andthe invention alsoconsists in a walk formed of stringers or sills covered with aseries ofplanks having the transverse middle portion of their upper surfaceshigher than the lateral edges thereof.

My invention is illustrated in the accompanying drawings, in the severalviews of which the letters of reference used in the followingdescription Will be found indicating the saine elements or parts.

Figure l is a transverse section of a plank having my improvedconstruction. Fig. 2 is the same in a modified form. Fig. 3 is anisometrical view of a section of walk containing my improvement.

d represents a plank, and b are its lateral edges. c is the under side,having a plane surface, and d is the upperside, provided with a convexform transversely, as shown in Fig. 3. The planks d are laid in seriesupon stringers or sills c with a narrow space f between their adjacentedges, and each plank is secured to the stringers by nails or otherwisein the usual manner. The Water falling upon the upper convex of theplank at once runs off at the side edges thereof and drips through thespaces between, so that in a short time after the rain has ceased tofall all water has run off and the surfaces of the planks are entirelydry and clean. The convexity of the upper surface of the plank is of adegree to allow the usual amount of warping to obtain and still havesufficient crown in the upper surface to allow the water to readily runoff, the lower surface of the plank being capable of absorbing onlymoisture sufficient to cause a certain degree expansion of the woodfiber to cause the warping, so that when this limit has been reached thewood cells then remain expanded, and the transverse curvature of theplank remains the same should the moisture be entirely evaporated andremoved. It Will be seen that this construction is of great benefit asto prolonging the period of Wearing of the plank, as the planks arequickly dried off and so cannot be thoroughly saturated from above,whereby a hard and solid upper surface is retained, while the center ofthe plank, be-

ing thicker than the edges thereof, provides a bracing property whichoperates to reduce the warping capacity and places the wear from useupon the transverse middle portion instead of upon the upraised edges ofthe planks commonly used for this purpose. This form of surface is ofgreat advantage when it is necessary toclean the Walk from snow, asascraper can be run over the walk Without catching upon the upturnededges of the planks and thereby obstructing the work or mutilating thewalk, while the shovel can be used with greater facility and ease, as bymoving the shovel slightly diagonal to the planks perfect freedom of theshovel is obtained and the Work is done with greater ease andperfection.

I Wish it understood, however, that I do not limit my improvement to anyparticular form of eonveXity for the upper side of the plank, as it maybe arranged With two plane surfaces inclined upwardly from the edges andmeeting in the middle or in proximity to the middle, as shown in Fig. 2.

Vhat I claim as my invention isl. A plank for Walks and bridges, havinga plane surface on its under side and having

